C++ 以最快的方式获取像素颜色？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/10515646/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Get Pixel color fastest way?
提问by Manitoba
I'm trying to make an auto-cliker for an windows app. It works well, but it's incredibly slow! I'm currently using the method "getPixel" which reloads an array everytime it's called.
我正在尝试为 Windows 应用程序制作一个自动点击器。它运行良好，但速度非常慢！我目前正在使用“getPixel”方法，每次调用时都会重新加载数组。
Here is my current code:
这是我当前的代码：
hdc = GetDC(HWND_DESKTOP);
bx = GetSystemMetrics(SM_CXSCREEN);
by = GetSystemMetrics(SM_CYSCREEN);
start_bx = (bx/2) - (MAX_WIDTH/2);
start_by = (by/2) - (MAX_HEIGHT/2);
end_bx = (bx/2) + (MAX_WIDTH/2);
end_by = (by/2) + (MAX_HEIGHT/2);
for(y=start_by; y<end_by; y+=10)
{
for(x=start_bx; x<end_bx; x+=10)
{
pixel = GetPixel(*hdc, x, y);
if(pixel==RGB(255, 0, 0))
{
SetCursorPos(x,y);
mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0);
Sleep(50);
mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
Sleep(25);
}
}
}
So basically, it just scan a range of pixel in the screen and starts a mouse event if it detects a red button.
所以基本上，它只是扫描屏幕中的一个像素范围，并在检测到红色按钮时启动鼠标事件。
I know there are other ways to get the pixel color, such as bitblt. But I've made some researches, and I don't understand how I'm supposed to do, in order to scan a color array. I need something which scans screen very fast in order to catch the button.
我知道还有其他方法可以获取像素颜色，例如 bitblt。但是我做了一些研究，我不明白我应该怎么做，以便扫描颜色阵列。我需要一些可以非常快速地扫描屏幕的东西才能抓住按钮。
Could you please help me?
请你帮助我好吗？
Thanks.
谢谢。
回答by Manitoba
I found a perfect way which is clearly faster than the GetPixel one:
我找到了一种完美的方法，它显然比 GetPixel 更快：
HDC hdc, hdcTemp;
RECT rect;
BYTE* bitPointer;
int x, y;
int red, green, blue, alpha;
while(true)
{
hdc = GetDC(HWND_DESKTOP);
GetWindowRect(hWND_Desktop, &rect);
int MAX_WIDTH = rect.right;
int MAX_HEIGHT = rect.bottom;
hdcTemp = CreateCompatibleDC(hdc);
BITMAPINFO bitmap;
bitmap.bmiHeader.biSize = sizeof(bitmap.bmiHeader);
bitmap.bmiHeader.biWidth = MAX_WIDTH;
bitmap.bmiHeader.biHeight = MAX_HEIGHT;
bitmap.bmiHeader.biPlanes = 1;
bitmap.bmiHeader.biBitCount = 32;
bitmap.bmiHeader.biCompression = BI_RGB;
bitmap.bmiHeader.biSizeImage = MAX_WIDTH * 4 * MAX_HEIGHT;
bitmap.bmiHeader.biClrUsed = 0;
bitmap.bmiHeader.biClrImportant = 0;
HBITMAP hBitmap2 = CreateDIBSection(hdcTemp, &bitmap, DIB_RGB_COLORS, (void**)(&bitPointer), NULL, NULL);
SelectObject(hdcTemp, hBitmap2);
BitBlt(hdcTemp, 0, 0, MAX_WIDTH, MAX_HEIGHT, hdc, 0, 0, SRCCOPY);
for (int i=0; i<(MAX_WIDTH * 4 * MAX_HEIGHT); i+=4)
{
red = (int)bitPointer[i];
green = (int)bitPointer[i+1];
blue = (int)bitPointer[i+2];
alpha = (int)bitPointer[i+3];
x = i / (4 * MAX_HEIGHT);
y = i / (4 * MAX_WIDTH);
if (red == 255 && green == 0 && blue == 0)
{
SetCursorPos(x,y);
mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0);
Sleep(50);
mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
Sleep(25);
}
}
}
I hope this could help someone else.
我希望这可以帮助别人。
回答by korona
The simple answer is that if this is the method you insist on using then there isn't much to optimize. As others have pointed out in comments, you should probably use a different method for locating the area to click. Have a look at using FindWindow, for example.
简单的答案是，如果这是您坚持使用的方法，那么就没有什么需要优化的了。正如其他人在评论中指出的那样，您可能应该使用不同的方法来定位要单击的区域。例如，看看使用 FindWindow。
If you don't want to change your method, then at least sleep your thread for a bit after each complete screen scan.
如果你不想改变你的方法，那么在每次完整的屏幕扫描后至少让你的线程休眠一段时间。
